Math Rules Flashcards
Divisibility Rules for Small Integers
What makes an integer X a multiple of an integer A?
X has all the prime factors of A.
Exponents: Base of 0 or 1
0 raised to ANY power = 0
1 raised to ANY power = 1
If x = x2 then x = 0 or 1
Exponents: Base of -1
(-1)ODD = -1
(-1)EVEN = 1
Exponential terms with common bases
Multiplying terms: add the exponents
Dividing terms: subtract the exponents
Anything raised to the Zero Power
Equals 1
EXCEPTION: 00 = UNDEFINED
Negative Exponents
Something with a negative exponent is just “one over” that same thing with a positive exponent
y-X = 1/(yX)
Nested Exponents
Multiply Exponents
(a2)3 = a6
How does the result change when fractions are multiplied by EVEN exponents?
< -1: Bigger
Between -1 and 0: Bigger
Between 0 and 1: Smaller
>1: Bigger
How does the result change when fractions are multiplied by ODD exponents?
< -1: Smaller
Between -1 and 0: Bigger
Between 0 and 1: Smaller
>1: Bigger
When the bases are identical and no other bases exist…
Drop the bases and rewrite the exponents as an equation
26w = 25w-5
6w = 5w-5
w = -5
Be careful if 0, 1, or -1 is (or could be) the base.
% Change Forumla
= Change / Original
Two operations that do NOT guarantee an integer answer/value even when starting wtih an integer
- Division
- Root
Definition of an integer
Negative or positive whole number and zero
Integers in a set (consecutive integers, consecutive multiples)
Conecutive Integers: (Last - First + 1)
Consecutive Multiples [(Last - First) / Increment] + 1
Properties of evenly spaced set
- The average (arithmetic mean) and median are equal to each other
* Note: For a set with an odd number of evenly spaced integers, the median/average will always be a member of the set. For a set with an even number of evenly spaced integers, the median/average will NOT be a member of the set.* - The mean and median of the set are equal to the average of the First and Last terms.
Sum of Consecutive Integers
Ex: Sum of positive integers up to 100, inclusive?
Sum of Evenly Spaced Set = Average x Number of Terms
Ex: Sum = Average x Number of Terms
Average (of Evenly Spaced Sets) = (First + Last)/2
Average = (1 + 100)/2 = 50.5
Number of Terms = (Last - First + 1)
Number of Terms = 100 - 1 + 1 = 100
Sum = 50.5 x 100 = 5050